Radio receiver



June 16, 1936, J. DREYFUS 2,044,759

RADIO RECEIVER Filed Aug. 1o, 1954 3 sheets-sheet 1 l INVENTOR vJEANDREYFUS BY Eg.

ATTORNEYS ---uwlwef:--- illzlsl 3 Sheets-Sheet 2 J EA N DR EYF U5 BY @gATToRN/Y SQ E SE June 16, 1936. J. DREYFUS RADIO RECEIVER Filed Aug. 1o,E934 June 16, 1936. J. DREYFUS RADIO RECEIVER 5' sheets-sheet 3 FiledAug. 10, 1934 Jean Dreyfu fwqmgzff.

c'rrweys' Patented June 16, 1936 PATENT oFFlsE .RADIO RECEIVER JeanDreyfus, Paris, France Application Augst 1o, 1934, serial No. 739,211 InFrance April 16. 1934 10 claims. (c1. 25o-14) Radio receiving sets arenormally provided with a tuning dial which makes it easy to note theparticular broadcasting stationsthat are received, and with a loudspeaker `for reproducing the v sounds transmitted by the electric waves.

In receiving sets heretofore constructed, the place of the dial` wasalways distinct from the mouth of the loud speaker. The object of thepresent invention is to provide a receiverin which thedial is positionedin the mouth of they loud speaker so as to better utilizethe spaceoccupied by the radio set. In this manner it is possible to increase thespace available for the dial, and therefore, to render the indications`on the dial more legible, while reducing the total space occupied bythe-set.

In constructing an arrangement of Athis character, it is necessary tomake theY dial `of a substance which is permeable to sound, or to use adial provided with suitable apertures. VAs long as this requirement iscomplied with; any 4kind of dial or indicating device and any kind ofloud speaker can be used in connection with theinvention. The dial maybe either movable :or stationary, and. visible either wholly or in partonly; it may carry gures, station names or technical characteristics.TheA indicating member `may `be either stationary or movable and may`include `a pointer which may be either mechanical or luminous. The loudspeaker may be oi any con-- struction such as electrodynamic,`electromagnetic, a permanentv magnet speaker, or speaker of theelectrostaticftype.

Preferably, however, according to the present invention, I providebetween Vthe dial and the tuning member a transmissiondevice including`a .cable connected with elastic return means, and a pulley Vof asuitably calculated outline, which device permits of disposing theituning parts at a suitable distance fromY the 4operating members toprevent interference `with the transmissionof sound and to obtain-aratio of transmission that varies according to any desired.predetermined law. Y

The dial itself may be either opaqueor transe lucent YandY illuminatedby transparency. In the `latter case,` the inscriptions are preferablyapplied to the rear face of the dial in such A'manner as to be invisiblewhen the dialaisin its dark or unilluminated condition. Y

The axis of the pointercooperatingwith the dial `4can be disposed inanyV position with respect yto the axis of the loudspeaker. Moreover,the pointer can be-disposed either in front of or behindlthe `dial. AInthe latterwcase :only the shadow fui of the pointer will be visible,when the dial is illuminated. Finally, the pointer may be of an opticalnature and to this end may consist of a neon tube in a known manner.

These and'other characteristic features of the 5 present invention willbe better understood from the following detailed description taken withreference to the accompanying drawings in which I have illustrated byway of example a preferred embodiment of the invention. In the drawings:10

Figure 1 is an elevational view of a'device embodying the invention; f

Y Figure 2 is a sectional View taken on the line II-II of Figure l;

Figure 3 is a partial View of Figure 2 on ,an en- 15 larged scale; Y

Figure 4 is a further detail view;

Figure 5 is a modification showing an optical system for a special Vformof tuning dial;

Figure `6 is a partial front view illustrating a 20 suitabletransmission mechanism for moving .the

pointer. N

SimilarV reference numerals identify similar parts throughout thedifferent views of the drawlngS. 25

The apparatus Vshown in Figures V1 and 2 of the drawings essentiallycomprises a casing l, made of wood or any other suitable material,housing a frame 2 carrying or enclosing the receiver or partsV such astubesfcoils, etc., including a vari- 30 -able tuningelement anda Vloudspeaker 3 electrically connected with the receiver.

The essential characteristic of the ,present invention resides in thefact that the dial 4 carry- Iing themarks thatpermit of identifying the35 emitting stations received, is mounted in thev .mouth of theloudspeaker, `thus occupying a space which is usually'wasted.

This dial should, therefore, be made of material "which is permeable toVsound waves and does 40 notdistort them, whileypermitting a legibleprinting of the indications the dial has to carry. As. already stated,the dial is preferably illuminated by transparency by means of a lamp 5in such manner that the inscriptions are visible only 45 Y `when thedial is illuminated. The material of which the dial 4is made should besuch as to distribute evenly the light coming from the `lamp andfurthermore it should not be affected `by the heat produced by the lampnor by variations vof the .humidity content of the surroundingatmosphere. Experiments `have shown that fabrics such as percale ororgandie, or the like, give'satisfactory results... The opacity of theindications 4carried Vby .the` dalmay be increased .by a deposit 55 of alayer of metallic dust, or by the application of a suitable coloringpowder.

In order to render the inscriptions completely invisible when the dialis not illuminated, I have shown a veil 6 provided in front of the dialwhich veil remains opaque as long as the lamp is disconnected and willbecome translucent when the lamp is lit. Experiments have shown thatfabrics such as crepe Georgette, Roman crepe or crepe de Chine fullysatisfy this double requirement. As the legibility, when the dial isilluminated is the better the finer the fabric of the veil, it isadvantageous to deposit the layer of typographic colouring matter on theinner surface of the dial Il, the printing being reversed The surface ofthe printed dial may be divided, in known manner, into as manyconcentric annular sections as there are diiferent ranges of wavelengths for which the receiver is constructed such as three ranges inthe example shown in the drawings.

The parts already described may be arranged in the following manner:

The loud speaker 3 is mounted against a suitable opening in the panel 'Iof the casing I and supported by an annular element 8. The two fabrics 4and 6 referred to are clamped against the edge of this opening by meansof a frame shown at 9. The lamp E, which preferably has a frosted bulb,is arranged in the axis of the loud speaker and has its base I0, mountedeither on the core of the loud speaker or on a bracket II mounted inturn upon a support I2 which may be carried by the frame 'I or by thecasing. The lamp may be placed at any desired point close to the dial.

Moreover, the diaphragm I3 of the loud speaker may act as a lightreflector. To this end its concave face is metallized or coated with alight colouring matter I4 capable of reflecting light evenly on to thedial and preventing the formation of sharp shadows of the parts placedbetween the lamp and the dial excepting the indicating pointer, as itwill be hereinafter explained. All these parts including the pointerwith its transmission mechanism, to be described, can be fitted in thecasing and fixed thereto by screws or similar means.

The pointer I5 may be disposed either in front of or behind the dial,preferably in the latter position so as to be invisible when thereceiver is not in operation. In order to render the pointer clearlyvisible through the translucent dial when the lamp is lit, it should bearranged in close proximity behind the screen 4.

In the embodiment shown in the drawings, the pointer is mounted at thecenter of the reflector and turns, together with the annular element I6and spindle I1 in a bearing I8 carried by the support I2.

The pointer serves to mark the indications carried by the dial either bysuperimposition or by framing them, by the provision of apertures I5aprovided in the pointer as shown in Fig. 4. The same pointer may serveto mark the indications of several groups of wave lengths by theprovision of a plurality of apertures I5a (three of which are shown inthe embodiment according to the drawings) cooperating with three zonesas wave length ranges a1, a2, a3 on the dial, as shown in Figure 1.

With the arrangement of the dial as described, it is advisable toprovide between the pointer and tuning members a transmission mechanismwhich is both simple and of light weight and which does not cause.interfering projecting shadows on the screen and does not distort orabsorb the sound Waves emitted by the loud speaker. Moreover, the ratioof transmission should vary according to a non-linear law, that is tosay, the ratio between the angles of rotation of the driving shaft andthe driven shaft should not be constant but should vary according to apredetermined law. In this manner it is possible to dispose the variousmarks carried by the dial at regular intervals, regardless of the law ofvariation of the tuning member, that is regardless of the angle of thecorresponding rotation of the shaft i9 by which the tuning member isoperated.

A mechanism satisfying these conditions is shown in Figure 5, andcomprises a pair of pulleys and 2I, keyed on shafts I'I and I9respectively, at least one of these pulleys, 2D for instance, having anon-circular outline determined in accordance with the law of variationof the ratio of transmission that it is desired to obtain.

Owing to this arrangement, the cable 22 does not form an endless orclosed band, but has one end fixed at a point on the periphery of thepulley 2| and the other end at a point of the periphery of pulley 20,which latter is urged in one direction by a return spring. For instancea pulley 22 fixed to pulley 2|] is connected with a coil spring 23secured at a fixed point 2Q of the casing as seen from Figure 5.

As is understood the device described is given merely by way of example,and various changes may be made in the construction and arrangement ofparts without departing from the spirit of the invention. Thus, the dialmay be either movable or stationary, it may be wholly or partly visible,it may carry figures, the names of the emitting stations, or technicalcharacteristics, disposed according to any system, etc., The indicatingmember may be either stationary or movable. The relative movement of thedial with respect to the pointer may be circular, or rectilinear, or ofany other kind.

Besides the aforementioned fundamental requirements, the insigniacarried by the dial could be capable of reproduction in an inexpensivemanner by a suitable industrial method of printing, such as by atypographie, lithographie, photographic process, by photogravure,off-set, phototype, and any other suitable process.

Basically the dial may have two general forms, (a) in the form of asemi-rigid plate, such as of Celluloid, provided with suitableapertures, and (b) in the form of a sheet of porous material such as afabric.

The first solution has the advantage of providing a dial on which theindications are very accurate while the second solution permits a morecomplete utilization of the available surface in front of the loudspeaker.

As regards the lighting device, it is to be observed that, in order tomark the different kinds of wave lengths, the indicating pointer may actas a support for one or more lamps projecting one or more luminous spotsonto the dial corresponding to the different wave length ranges.

Finally, the dial may carry no material mark, the necessary indicationsbeing applied to a separate transparent plate of smaller dimensions andbeing projected on to said dial by the luminous system disposed in theloud speaker. This is diagrammatically shown in Figure 5, wherein lamp21 projects the transparent dial plate indications at 28 by means of aprojecting lens system 29 upon the sound permeable fabric 6.

While I have Vdescribed what I deem to be Va practical and eicientembodiment of the present invention, it should be understood that I donot wish to be limited thereto as various changes may be made in thearrangement, disposition and form ofthe parts without department fromthe principle of the present invention as comprehended within the scopeof the claims hereunto annexed.

What I claim is:

1. A radio receiver which comprises in combination, a loud speaker, asound pervious tuning dial occupying a sound emitting oriiice in thefront of said radio receiver and carrying tuning inscriptions upon therearV surface thereof, and a source of light disposed behind the tuningdial capable of rendering the tuning inscriptions upon said tuning dialvisible by the translucent character of the..latter.

2. A radio receiver which comprises Vin combination, a loud speaker, adial disposed in front of the mouth of said loud speaker, means forilluminating said dial from the back thereof, said dial carryinginscriptions arranged to be visible only when said means areilluminating said dial, and a veil disposed in front of said dial andmade of such a material as to be opaque when not illuminated from behindand transparent when illuminated from behind. y

3. A radio receiver according to claim l further including a movablepointer disposed behind the tuning dial in order to be normallyconcealed thereby and so that only its shadow is visible on the tuningdial when the latter is illuminated.

4. A radio receiver according to claim l further comprising a lightdiffusingV surface means for illuminating the tuning dial byreflection.l

5. A radio receiver according to claim 1 further including a membranefor said loud speaker'acting as a light diffusing surface forilluminating the dial by reection.

6. A radio receiver which comprises in combination, a loud speaker, a.sound pervious tuning dial disposed in the path of sound produced by theloud speakerV and translucent when illuminated, a source of light behindsaid dial, and a transparent plate carrying the tuning inscriptions tobe seen on the dial interposed between said source and said dial,whereby said inscriptions are projected onto said dial.

7. In a radio receiver, the combination of a loud speaker terminating inan oriiice and a sound permeable fabric screen disposed across the frontof the loud speaker having tuning indicia thereon arranged within thecircumferential edge of the orifice of the loud speaker. Y

8. In a radio receiver, the combination of a loud speaker terminating inan orice, a sound permeable screen disposed across the front of the loudVspeaker having tuning indicia thereon arranged within thecircumferential edge of the orice of the loud speaker, and lightingmeans behind said screen to cause light to appear through the screen andreveal the tuning indicia thereon.

9. In a radio receiver as claimed in claim 8, a

pointer movable with respect to said screen, a y

control member for said pointer, and a transmission device between saidmember and said pointer, said device being constructed so as to oier nosubstantial resistance to the passage of sounds and being arranged togive a ratio of transmission between said control member and saidpointer which is variable in accordance with the position of saidpointer.

10. In a radio receiver as claimed in claim 8, a pointer rotatablymounted with respect to said screen, a control member for said pointer,a pulley connected to said member, a further pulley angularly connectedwith said pointer, at least one of said pulleys having a profile outlinecorresponding to a predetermined decrease of relative movement of thepointer and its pulley toward one end of the range of movement of saidpointer with respect to the movement of the other pulley, a cable vwound around vsaid pulleys and fixed at one end

